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audio/softsynth/cms.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef AUDIO_SOFTSYNTH_CMS_H
+#define AUDIO_SOFTSYNTH_CMS_H
+
+#include "audio/cms.h"
+
+/* this structure defines a channel */
+struct saa1099_channel {
+	int frequency;				/* frequency (0x00..0xff) */
+	int freq_enable;			/* frequency enable */
+	int noise_enable;			/* noise enable */
+	int octave;				/* octave (0x00..0x07) */
+	int amplitude[2];			/* amplitude (0x00..0x0f) */
+	int envelope[2];			/* envelope (0x00..0x0f or 0x10 == off) */
+
+	/* vars to simulate the square wave */
+	int32 counter;
+	int32 freq;
+	int level;
+};
+
+/* this structure defines a noise channel */
+struct saa1099_noise {
+	/* vars to simulate the noise generator output */
+	int32 counter;
+	int32 freq;
+	int level;				/* noise polynomal shifter */
+};
+
+/* this structure defines a SAA1099 chip */
+struct SAA1099 {
+	int stream;				/* our stream */
+	int noise_params[2];			/* noise generators parameters */
+	int env_enable[2];			/* envelope generators enable */
+	int env_reverse_right[2];		/* envelope reversed for right channel */
+	int env_mode[2];			/* envelope generators mode */
+	int env_bits[2];			/* non zero = 3 bits resolution */
+	int env_clock[2];			/* envelope clock mode (non-zero external) */
+	int env_step[2];			/* current envelope step */
+	int all_ch_enable;			/* all channels enable */
+	int sync_state;				/* sync all channels */
+	int selected_reg;			/* selected register */
+	struct saa1099_channel channels[6];	/* channels */
+	struct saa1099_noise noise[2];		/* noise generators */
+};
+
+class DOSBoxCMS : public ::CMS::CMS, public Audio::EmulatedChip {
+public:
+	DOSBoxCMS(uint32 basePort = 0x220) {
+		memset(_saa1099, 0, sizeof(SAA1099)*2);
+		_basePort = basePort;
+	}
+
+	~DOSBoxCMS() override { }
+
+	bool init() override;
+	void reset() override;
+	void write(int a, int v) override;
+	void writeReg(int r, int v) override;
+
+	bool isStereo() const override { return true; }
+
+protected:
+	void generateSamples(int16 *buffer, int numSamples) override;
+
+private:
+	uint32 _basePort;
+
+	SAA1099 _saa1099[2];
+
+	void envelope(int chip, int ch);
+	void update(int chip, int16 *buffer, int length);
+	void portWriteIntern(int chip, int offset, int data);
+};
+
+
+#endif